Characterization of Ethyl Acetate and Trichloromethane Extracts from Phoebe zhennan Wood Residues and Application on the Preparation of UV Shielding Films

Abstract

In this work, ethyl acetate (EA) and trichloromethane (TR) extracts were extracted from Phoebe zhennan wood residues and the extracts were then applied to the preparation of UV shielding films (UV-SF). The results revealed that substances including olefins, phenols and alcohols were found in both EA and TR extracts, accounting for about 45% of all the detected substances. The two extracts had similar thermal stability and both had strong UV shielding ability. When the relative percentage of the extract is 1 wt% in solution, the extract solution almost blocked 100% of the UV-B (280–315 nm), and UV-A (315–400 nm). Two kinds of UV-SF were successfully prepared by adding the two extracts into polylactic acid (PLA) matrix. The UV-SF with the addition of 24 wt% of the extractive blocked 100% of the UV-B (280–315 nm) and more than 80% of the UV-A (315–400 nm). Moreover, the UV shielding performance of the UV-SF was still stable even after strong UV irradiation. Though the addition of extracts could somewhat decrease the thermal stability of the film, its effect on the end-use of the film was ignorable. EA extracts had less effect on the tensile properties of the films than TR extracts as the content of the extract reached 18%. The results of this study could provide fundamental information on the potential utilization of the extracts from Phoebe zhennan wood residues on the preparation of biobased UV shielding materials.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…Upon accelerated exposure with UV radiation of up to 960 h, coatings with bark extractives using ethanol reduced the discolouration to about 65% of that for the control wood surfaces. A 1 wt % solution of the extractives of Phoebe zhennan wood with polar solvents completely absorbed solar UV-A and UV-B radiation in laboratory studies [ 441 ]. UV-shielding films of poly(lactic acid) with 24 wt% of wood extract screened out all of UV-B and 80% of UV-A radiation.…”

Proanthocyanidins in Pruning Wood Extracts of Four European Plum (Prunus domestica L.) Cultivars and Their hLDHA Inhibitory Activity

“…Regarding AcOEt extracts, cultivar ‘De la Rosa’ (3.3 %) showed the higher yield followed by the two samples of ‘Reina Claudia Verde’ (2.4 % and 1.8 %). These extraction yields are higher than those of other woods from agricultural wastes processed by us in the past, such as olive wood (1.6 % yield), [29] sweet cherry wood (0.9 % yield) [32] or laurel wood (0.3–0.8 % yield), [31] and of the same order of magnitude than other useful woods like, for example, Phoebe zhennan wood residues (3.8 % yield) [42] …”

“…These extraction yields are higher than those of other woods from agricultural wastes processed by us in the past, such as olive wood (1.6 % yield), [29] sweet cherry wood (0.9 % yield) [32] or laurel wood (0.3 -0.8 % yield), [31] and of the same order of magnitude than other useful woods like, for example, Phoebe zhennan wood residues (3.8 % yield). [42] Total Phenolic Content and Antioxidant Activity of European Plum Wood Extracts…”

Effects of UV radiation on natural and synthetic materials

“…Wood bark extracts are particularly rich in polyphenols including condensed tannins and flavonoids, which are very good absorbers of UV radiation. For instance, a 1 wt% solution of the extractive of Phoebe zhennan wood by polar solvent ethyl acetate completely absorbs solar UV-A and UV-B wavelengths in laboratory studies [ 109 ]. The extractives accounted for 3.8 wt% of the wood.…”